WASHINGTON (CNN) -- Congress launched a formal debate on reforming the ailing U.S. health care system Wednesday with a Senate committee considering a comprehensive bill backed by Democrats and the Obama administration.

Sen. Christopher Dodd said that health care reform efforts date back 60 years.

The measure before the Senate Health, Education, Labor and Pension Committee includes a government-funded health insurance option opposed by Republicans, along with mandates for individual and employer-sponsored health coverage.

Also Wednesday, House Republicans unveiled the outline of a competing plan that offers refundable tax credits to lower-income Americans to help them afford private health insurance.

At issue is how to reduce the costs and increase the reach of the current health care system, which officials say is increasingly draining the federal budget but leaving 46 million Americans without health insurance.

Obama has made the issue a top priority of his young administration, warning that failure to act now will bring far worse economic difficulties in the future than the costs of plans under discussion.

Republican opponents complain that the government and the Democratic leadership are moving too fast, noting that preliminary cost estimates for the bill are incomplete.

The Senate hearing Wednesday started 15 minutes late because of the lack of a quorum, and Republican members immediately questioned the wisdom of debating and amending the bill without having full cost estimates.

Sen. Christopher Dodd, D-Connecticut, the acting committee chairman in the absence of ailing Democratic colleague Sen. Ted Kennedy of Massachusetts, said it was important to start the hearing on what he called "historic" legislation that will affect every American.

The bill submitted in Kennedy's name proposes "building on what works and fixing what's broken in our health care system," a Democratic mantra for the issue.

A summary of the measure guarantees people can keep their current health insurance if they want while offering government-funded coverage for those without insurance or who are unable to afford full coverage.

Dodd noted that efforts to reform health care date back 60 years and called it a moral imperative to provide proper health care for all citizens regardless of circumstances.

"The status quo is unacceptable, and it is unsustainable," Dodd said, adding that former opponents of reform now are taking part in the effort. He cited main elements of the measure, including a government-funded option, an emphasis on preventive care to reduce costs and a halt to pre-existing medical conditions making coverage unavailable.

Republicans complained the bill before them would fail to achieve those goals.

"This bill costs too much, covers too few and will force about 10 million people to have to lose their employer-provided coverage," said Sen. Michael Enzi of Wyoming, the ranking Republican on the committee. He blamed what he called the rushed timetable for considering the bill on a need to address how spiraling health care costs were harming the economy, but said the proposal drafted by Democrats alone would increase costs.

"We need a bill that won't destroy the economy," Enzi said.

Don't Miss

Meanwhile, the House Republican plan by ranking Ways and Means member Dave Camp of Michigan calls for refundable tax credits for lower-income Americans. But Camp and Republicans have not yet determined key details, including the amount of those tax credits or who precisely could be eligible.

"We're going to provide a dollar amount to people who want to buy insurance," Camp told CNN Radio on Tuesday. "The numbers are going to depend on how (the ideas) are scored."

Scoring is the process for determining how much a proposal could cost. Camp and Republicans are waiting to see the relative expense of different proposals before committing to specifics.

"That will come later," Camp said, insisting the Republican bill will be "much less costly than the Democratic bills."

Highlights of Camp's measure include letting states, small businesses and other group pool together to offer lower-cost health care plans and allowing Medicaid users to take the value of their Medicaid benefit and transfer or apply that to a private health care plan instead.

It also calls for limiting malpractice lawsuits to drive down the costs of "defensive" health care, in which unnecessary tests and services are prescribed to avoid possible malpractice liability.